1. FIELD OF THE INVENTION
This invention relates generally to knurling tools for use by rotary metal working machines such as automatic screw machines, lathes, CNC machines and the like. More particularly, the present invention is directed to modular knurling tools having a tool shank adapted for support by the tool support of a metal working machine and defining an adjustable connector to which any one of several types of knurling heads is releasably and adjustably connected and selectively and securely locked.
2. DESCRIPTION OF THE PRIOR ART
Typically, knurling tools have been provided having a tool body having a shank that is of a dimension for mounting by the tool holder assembly of a lathe, CNC or other type of metal working machine so that one or more knurling wheels, rotatably supported by the knurling tool body, can be positioned in forcible engagement with a rotatable workpiece to thus knurl or deform the outer surface of the workpiece and define a desired knurling pattern. Typically, the only component of the knurling tool that is replaceable is the knurling wheels. These knurling tools are usually designed to form only a single knurling pattern so that changing the knurling pattern requires replacement of the knurling wheel or wheels. If a different type of knurling pattern is desired it is often more practical, rather than replace the knurling wheels of a particular tool, to acquire a separate knurling tool with the desired wheel pattern. Many times work piece knurling activities require a knurling tool having two knurling wheels oriented in angular relation with one another so that the patterns of the knurling wheels will overlap on the work piece to provide a desired composite pattern. In such case it is often necessary to acquire a special knurling tool to produce this desired knurling pattern on work pieces. Because of these conventional knurling tool practices it is typical for machining organizations to eventually accumulate a large number of knurling tools, thus requiring significant machine tool capital investment and requiring significant tool crib organization and control activities for efficient operation of a machining business. All of these factors constitute impediments to the commercial success of work piece knurling operations by increasing the ultimate costs of machining operations.
Over the years a number of others have determined the feasibility of providing knurling tools that can be adjusted or converted so as to provide the capability for accomplishing a number of differing knurling tasks with a single adjustable knurling tool. Examples of such adjustable knurling tools and adjustable or convertible tools in general are represented by U.S. Pat. No. 1,492,814 of Sheberashenko; U.S. Pat. No. 2,436,950 of Boyer; U.S. Pat. No. 2,796,779 of Miller; U.S. Pat. No. 3,972,212of Brinkman and U.S. Pat. No. 5,046,226 of Che. The problem with most adjustable machine tools of this nature is the lack of stability or rigidity during machining operations, which compromises the quality of the machining operations that can be accomplished. For quality machining operations, including knurling operations, the machine tools must be absolutely immovable during machining operations, even when placed under heavy load or operated at high speed for high production. The adjusting mechanisms with which most of these types of machine tools are provided typically allow some tool movement, especially when the tools are being used under heavy load or at high speed. It is desirable therefore to provide a modular knurling tool having the capability for efficiently stabilized rotary support of single, dual or multiple knurling wheels so that the resulting knurling operation will be of high quality and high performance. Since set-up time is also a problem that interferes with the commercial feasibility of adjustable machine tools of any type, it is desirable to provide a modular knurling tool having a single tool shank that can be set up by the tool holder of a machine in the usual fashion. The mounted tool shank is adapted to receive any one of a number of knurling heads without necessitating its removal from the tool holder. This feature will allow knurling heads to be easily and simply interchanged as needed for variation in the character of knurling that is desired and will allow a machining facility to maintain a minimum number of tool shanks, thus also minimizing the overall machine tool inventory that is necessary for operation of the machining facility. It is also desirable to provide a modular knurling tool that, without disturbing the mounting of the tool shank in the tool holder of a metal working machine, can be simply and efficiently adjusted with respect to the work piece being knurled so that knurling operations can continue with a minimal of delay in the event adjustment becomes desirable.
When adjustable knurling tools are utilized they are typically of such bulky nature that work pieces cannot be knurled close to or against a square work piece shoulder. It is desirable to provide a modular knurling tool having a tool shank that is adapted to receive a knurling head having one or more outboard knurling wheels that are so located with respect to the tool head that cylindrical surfaces of work pieces intersecting abrupt shoulders can be provided with knurling.
One of the problems that typically plague high performance, high speed knurling operations is the high degree of wear that knurling wheels encounter as they are subjected to high speed knurling while heavy force is being applied, thus subjecting the knurling wheels to significant heat and significant thrust loads. It is also desirable to provide a modular knurling system which incorporates knurling wheels and knurling wheel support that will effectively accommodate the heavy thrust loads and resist heat buildup during high speed and high performance knurling operations.